In the fiberglass reinforced plastics (FRP) industry, selecting the right ventilation technology to meet OSHA’s styrene emission requirements means find- ing – as one manufacturer states it – a system that delivers the right amount of air, in the right location, in the right quantity for the right amount of time. To meet these requirements, Zadro installed a state- of-the-art ventilation system when the company moved to a new, larger facility in November of 2007.
But today’s state-of-the-art systems go far beyond simple air delivery. These advanced systems incor- porate digital controls and energy saving heat recov- ery technology to not only reduce emissions and control dust from grinding operations, but also pro- vide the worker with the ideal temperature for com- fort and the process too.
These ventilation systems are so sophisticated and energy efficient, in fact, that they have turned what is traditionally the least desirable work area in a plant into a show room.
All manufacturers and fabricators must comply with EPA and OSHA regulations as well as similar State regulatory authorities regarding the emission of styrene, which is released in the plant work space and into the environment during the manufacturing process.
FRP-specific system or HVAC?
For manufacturers like Zadro, the first question is where to look. Typically, ventilation systems have been designed and constructed by general HVAC contractors. However, these systems are not designed specifically for the needs of FRP manufac- turers.
According to Zadro, general mechanical contractors lacked the knowledge of the fiberglass process and were essentially “learning on the job.” As a result, he selected a system from Frees Inc. (Shreveport, LA), a specialist in ventilation systems for the fiber- glass industry for over two decades. He was aware of the company because of its regular presence at industry trade shows.
“Frees not only had the engineering and the science, but they also had the expertise and experience on the fiberglass side,” says Zadro.
Unfortunately, dilution ventilation typical demands a tremendous volume of outside air that must be brought in, heated to 70-75 degrees and then exhausted. Furthermore, if the worker is in a con- centrated emissions zone, it is difficult to get the air to a specific spot using this technique.
According to Zadro, the system he installed from Frees Inc., is not based on dilution ventilation, but is instead a directed air flow system designed to venti- late the breathing zone of the worker, not the entire building.
In the United States, OSHA PEL (permissible expo- sure levels) requirements for styrene require that the breathing zone within the workplace average less than 50 ppm (parts per million) over an 8 hour peri- od.
Owen Maxwell, vice president of product develop- ment of offshore fishing boat manufacturer Regulator Marine, also selected Frees Inc. because of its in-depth knowledge of the industry.
However, with so many regulatory agencies the rules can change in a hurry. Canadian fiberglass manufacturer Structural Composite Technology dis- covered, to its surprise, that the provincial govern- ment in Winnipeg, Manitoba had tightened require- ments to a remarkably low 20 ppm. This was far below the 50 ppm in the U.S. and other parts of Canada and represented a more than 40% reduction from previous limits. “Here in Manitoba, if a plant averages over 20 ppm, the workers must wear a respirator, when if you were in North Dakota – just south of us – you didn’t have to,” says John Zadro, president of Structural Composite Technology. “And if you were in Ontario or Alberta or Saskatchewan, they didn’t have to either.”
“I was impressed by their overall knowledge of the open mold fiberglass industry,” says Maxwell. “They had been in and out of every major boat builder’s shop so they had seen what was working and what was not working,” says Maxwell.
The directed air flow system is a proprietary solu- tion that can focus air in a controlled envelope that moves across the breathing zone and then “stops” (to prevent roll back and re-contamination of the work area), is captured, and then removed from the area. The contaminated air is forced out high enough for dispersion or routed through an end of stack (EOS) control as mandated by the user’s emis- sion permit.
Maxwell briefly considered other options, including HVAC contractors, when the company moved to a new plant. “They were learning as they were build- ing these systems and some worked and some did- n’t. We just didn’t want to be an experiment,” explains Maxwell. “There really is an art to how the system controls this air envelope,” explains Zadro. “The analogy is like blowing air around a lit candle, getting rid of the smoke, while not affecting the flame. With this system, our shop is regularly less than 20 ppm.”
Dilution ventilation versus directed air flow
Most ventilation systems depend upon a methodology called dilution ventilation in an attempt to meet OSHA’s PEL requirements. The basic premise is to calculate and bring in enough fresh air to dilute the styrene levels to the required levels. A directed air flow system requires approximately 40-60% as much air as a conventional ventilation system. Because less air is required, the system demands less equipment, operating costs, and main- tenance and therefore typically costs less than con- ventional systems.
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